/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    SingleClassifierEnhancer.java
 *    Copyright (C) 2004-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.classifiers;

import java.util.Collections;
import java.util.Enumeration;
import java.util.Vector;

import weka.classifiers.rules.ZeroR;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.CommandlineRunnable;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Utils;

/**
 * Abstract utility class for handling settings common to meta classifiers that
 * use a single base learner.
 *
 * @author Eibe Frank (eibe@cs.waikato.ac.nz)
 * @version $Revision$
 */
public abstract class SingleClassifierEnhancer extends AbstractClassifier {

    /** for serialization */
    private static final long serialVersionUID = -3665885256363525164L;

    /** The base classifier to use */
    protected Classifier m_Classifier = new ZeroR();

    /**
     * String describing default classifier.
     */
    protected String defaultClassifierString() {

        return "weka.classifiers.rules.ZeroR";
    }

    /**
     * String describing options for default classifier.
     */
    protected String[] defaultClassifierOptions() {

        return new String[0];
    }

    /**
     * Returns an enumeration describing the available options.
     *
     * @return an enumeration of all the available options.
     */
    public Enumeration<Option> listOptions() {

        Vector<Option> newVector = new Vector<Option>(3);

        newVector.addElement(new Option("\tFull name of base classifier.\n" + "\t(default: " + defaultClassifierString() + ((defaultClassifierOptions().length > 0) ? " with options " + Utils.joinOptions(defaultClassifierOptions()) + ")" : ")"), "W", 1, "-W <classifier name>"));

        newVector.addAll(Collections.list(super.listOptions()));

        newVector.addElement(new Option("", "", 0, "\nOptions specific to classifier " + m_Classifier.getClass().getName() + ":"));
        newVector.addAll(Collections.list(((OptionHandler) m_Classifier).listOptions()));

        return newVector.elements();
    }

    /**
     * Parses a given list of options. Valid options are:
     * <p>
     *
     * -W classname <br>
     * Specify the full class name of the base learner.
     * <p>
     *
     * Options after -- are passed to the designated classifier.
     * <p>
     *
     * @param options the list of options as an array of strings
     * @exception Exception if an option is not supported
     */
    public void setOptions(String[] options) throws Exception {

        super.setOptions(options);

        String classifierName = Utils.getOption('W', options);

        if (classifierName.length() > 0) {
            setClassifier(AbstractClassifier.forName(classifierName, null));
            setClassifier(AbstractClassifier.forName(classifierName, Utils.partitionOptions(options)));
        } else {
            setClassifier(AbstractClassifier.forName(defaultClassifierString(), null));
            String[] classifierOptions = Utils.partitionOptions(options);
            if (classifierOptions.length > 0) {
                setClassifier(AbstractClassifier.forName(defaultClassifierString(), classifierOptions));
            } else {
                setClassifier(AbstractClassifier.forName(defaultClassifierString(), defaultClassifierOptions()));
            }
        }
    }

    /**
     * Gets the current settings of the Classifier.
     *
     * @return an array of strings suitable for passing to setOptions
     */
    public String[] getOptions() {

        Vector<String> options = new Vector<String>();

        options.add("-W");
        options.add(getClassifier().getClass().getName());

        Collections.addAll(options, super.getOptions());

        String[] classifierOptions = ((OptionHandler) m_Classifier).getOptions();
        if (classifierOptions.length > 0) {
            options.add("--");
            Collections.addAll(options, classifierOptions);
        }

        return options.toArray(new String[0]);
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String classifierTipText() {
        return "The base classifier to be used.";
    }

    /**
     * Returns default capabilities of the base classifier.
     *
     * @return the capabilities of the base classifier
     */
    public Capabilities getCapabilities() {
        Capabilities result;

        if (getClassifier() != null) {
            result = getClassifier().getCapabilities();
        } else {
            result = new Capabilities(this);
            result.disableAll();
        }

        // set dependencies
        for (Capability cap : Capability.values())
            result.enableDependency(cap);

        result.setOwner(this);

        return result;
    }

    /**
     * Set the base learner.
     *
     * @param newClassifier the classifier to use.
     */
    public void setClassifier(Classifier newClassifier) {

        m_Classifier = newClassifier;
    }

    /**
     * Get the classifier used as the base learner.
     *
     * @return the classifier used as the classifier
     */
    public Classifier getClassifier() {

        return m_Classifier;
    }

    /**
     * Gets the classifier specification string, which contains the class name of
     * the classifier and any options to the classifier
     *
     * @return the classifier string
     */
    protected String getClassifierSpec() {

        Classifier c = getClassifier();
        return c.getClass().getName() + " " + Utils.joinOptions(((OptionHandler) c).getOptions());
    }

    @Override
    public void preExecution() throws Exception {
        if (getClassifier() instanceof CommandlineRunnable) {
            ((CommandlineRunnable) getClassifier()).preExecution();
        }
    }

    @Override
    public void postExecution() throws Exception {
        if (getClassifier() instanceof CommandlineRunnable) {
            ((CommandlineRunnable) getClassifier()).postExecution();
        }
    }
}
